1. Field of the Invention
The present invention relates to door locks for ranges and ovens, and more particularly, to motorized range and oven locks for the doors of self-cleaning ovens.
2. Description of Related Art
Modern ovens are often equipped with the capability to self-clean. Self-cleaning is accomplished by heating the oven to temperatures of approximately 400.degree.-480.degree. C. (750.degree.-900.degree. F.). Self-cleaning ovens typically employ a locking mechanism to lock the oven door during the cleaning operation. Existing door locks take various forms, the most advanced of which will automatically lock the door at the beginning of the cleaning operation and automatically unlock the door when the oven reaches a predetermined reduced temperature.
Some existing automatic door locks employ motors to actuate the lock. One example is described in U.S. Pat. No. 4,927,996. Conventionally, ovens use A.C. powered circuits. Therefore, existing motorized oven locks, such as disclosed in the referenced patent, employ A.C. motors. With the advent of microprocessor controllers, some advanced ovens have been provided with a low-voltage D.C. powered microprocessor controller and a low-voltage D.C. power supply for powering the controller. The D.C. microprocessor controller thus controls the lock motor and other functions according to a predetermined program. In microprocessor controlled ovens, D.C. controlled relays are added for switching A.C. powered devices such as the lock motor. The addition of a relay to control the lock motor adds to the cost of the oven and increases the number of parts and the possibility of a malfunction.
A problem facing oven designers is the protection of the motor and lock parts from the intense heat of the oven cavity. The usual location of an oven door latch is at the top center of the door, which, particularly during the self-cleaning operation, is a hot location. Existing self-cleaning ovens often have the oven lock motor mounted remotely from the door latch in a relatively cool location. In these designs, a linkage connects the door latch with the motor. Some designs incorporate a cooling fan to cool the motor and actuating mechanism. In addition, heat shields and insulation are used to isolate the door latch motor from the hot oven cavity. The measures used to protect the motor and actuating mechanism from heat add significant cost to the oven. There is a need for a heat-resistant unitary lock mechanism which can be mounted to the front center latch position of an oven.